Circuit breaker



Aug. 5, 1941. w. H. FRANK ETAL 2,251,703

CIRCUIT BREAKER Original Filed Nov. '7. 1934 25a 224 105 1 8 104 o O 234 109 Patented Aug. 5, 1941 CIRCUIT BREAKER William H. Frank and Joseph A. Messing, Detroit, Mich., assignors to Bulldog Electric Products Company, Detroit, Mich., a corporation of West Virginia Original application November 7, 1934, Serial No. 751,834, now Patent No. 2,072,163, dated March 2, 1937. Divided and this application September 3, 1936, Serial No. 99,265. Renewed October 11, 1939 17 Claims.

This application relates to circuit controlling means or circuit breakers and particularly to details of construction thereof, and is a division of our application Serial No. 751,834, filed November '7, 1934, which became Patent No. 2,072,163 on March 2, 1937.

For an understanding of the circuit breaker here disclosed, reference will be had to the appended drawing. In this drawing,

Figs. 1, 2a and 2b show the circuit breaker in various positions.

In Figs. 1, 2a, and 2b there is disclosed a circuit breaker employing a magnet IOI surrounding core or plunger I02 connected through a link I03 to a breaker contact arm I04 by a pin and slot connection at I05. A latch 224 on the link I03 is normally caught under a cross piece 201, restrained against movement to the right for release of link I03, by the tip I08 of a thermal control element I09. Pedestals IIO, III support the contact arm I04 and the cross piece 201.

The operation of this form of circuit breaker is as follows: When an ordinary or moderate overload occurs, the magnet IN is energized and tends to pull arm I04 upwardly to break the circult. However, unless the overload has endured sufliciently long to warp element I09 to the right and to move cross link 201 to the right, the magnet cannot effect circuit breaking since the link I09 is held down by the cross piece 201. After a predetermined interval of overload, the warping element I09 releases the parts for circuit break- I magnet will positively and quickly effect circuit breaking.

For a heavy overload or short circuit, instantaneous break ought to be provided, and for this purpose there is provided a quick break means including an armature IIB, pivoted at II1, to a pedestal H0. 0n heavy overload, this armature will be attracted by the solenoid to overcome the action of the spring I I9 and force the thermal element I09 to the right and thus allow the circuit breaker to trip instantaneously.

It will be seen that the construction here shown includes parts so arranged that the speed of release will vary with the intensity of the overload, which is a desirable characteristic; and that we provide a belated release for moderate overloads, through thermally responsive means,

- and an instantaneous release for heavy overloads,

through magnetic means. It will also be noted that the same magnet is used for moving the contact arm I04 and for magnetic trip of the holding means I09 through the actuation of the instantaneous breaking means, the armature I I6.

To close the breaker, the plunger I02 and with it the link I03 may be moved down manually, until latch 224 snaps down past the cross piece 201. Or, if desired, reliance may be placed on gravity to move the plunger I02 and link I03 down until latch 224 snaps past cross piece 201, the parts here functioning to close the breaker automatically.

If it be found that gravity alone is not sumcient to cause automatic closing, as for example, when the breaker is mounted in any position but the one shown, the spring 226 may be utilized to move the plunger I02 out of the magnet for automatic closing. I

It will be observed that since, in the breaker of Fig. 1, the automatic closing action takes place when the thermal element I09 cools, the right end of the cross piece 201 is moved with the tip I08 of the thermal element when the thermal element returns to its original holding position. This characteristic automatically insures proper timing of the operation of the parts and insures the thermal element functioning as a ,holding means for core I02 immediately upon its return without further manipulation on the part of the operator.

The breaker of Fig. 1, which is of the automatic closing type, will close itself automatically, soon after the circuit is broken, due to the consequent immediate deenergization of magnet IN, and thermal latch I09, and the cooling and return of such latch. Under certain circumstances, as where the overload is a continuing one, the breaker will automatically open and close in cycles, and these will be so frequent that the contacts at II4 will soon burn out, not having time to cool between cycles. For this reason we provide means for delaying the automatic closing action so that the cycles of automatic opening and closing will not be so frequent, even when the overload is continued. Such means is shown in the breaker shown here, and such means, to be known as means for delaying automatic closing operation, will now be described.

The cross piece 201 is mounted to reciprocate between rollers 220 mounted on pedestal II I, and is formed with 9. lug 22I cooperating with the lower end of the pivoted armature H6, whereby the quick acting armature may form a holding means for the cross piece, overcontrolling the delayed action of the thermal element whose tip is received in a groove 222 of the cross piece. The cross piece is formed with a slot 223 formed to cooperate with the latch 224 pivotally mounted on the link I03 and urged by a spring to assume the position shown, with the latch engaging a stop 225 formed on the link I03, the latch, however, being movable, in opposition to the spring, from the position shown, in a counterclockwise direction.

The operation of the circuit breaker, when equipped with the above described means for delaying automatic closing operation, will now be described. On the arising of an overload of suflicient duration or degree, the thermal element I 09 will warp to the right, pulling cross piece 201' with it, whereupon the right end of slot 223 will clear the right end of latch 224. Immediately thereafter, link I03 will move up to break the circuit, after which latch 224, which had been moved counterclockwise as link I03 moved up, returns to its original position with its lower edge resting upon the upper surface of the cross piece 201. The parts will now be held in circuit open position against the influence of the contact arm return spring 226 until thermal element I09 cools and returns to its original position. When this happens, cross piece 201 will be moved to the left and the lower part of latch 224 will clear the slot and link I03 will drop, due to the influence of the return spring 226, after which the latch 224, which had been moved counterclockwise as the link I03 moved down, returns to its original position with its upper edge resting under the latch surface of the cross piece 201 as shown in Fig. l, the circuit being remade automatically. Thus it will be seen that automatic closing is accomplished, but is delayed until after the thermal element I09 has had sufficient time to cool.

It is to be noted that the function of the latch 224 is to prevent strain on the thermal element during movement of the plunger I02. Latch 224 might be omitted and replaced with corresponding projections or lugs on the plunger member I03. However, in this event the thermal element would be strained as the plunger I03 was moved.

In order to provide a manual control for the breaker, for manual switching action, there is provided a manually accessible handle 230 pivoted at 23I on a pedestal 232, and having a cam roller 233 adapted to ride on the upper edge of the curved end 234 of the contact arm I04. When the handle is in the position of Fig. 1 the parts will be free to make or break the circuit in accordance with the movements of the thermal element I09. However, the handle 230 may be moved manually to the position of Fig. 2a, whereupon the circuit is broken. With the handle in this position, automatic closing is not possible because the handle acts as a bar against movement of the contact arm I04 from the position of Fig. 2a, wherein the circuit is broken, to the circuitmaking position of Fig. 1, the parts being so proportioned that the pressure created by the return spring 226 on the contact arm I04 acts through the center line of the roller 233 and the pivot 23I.

One very important consideration of the construction of this case is the characteristic that the breaker operates with a quick break and quick make switching action on overload. This is accomplished by providing the breaker with a force (the magnet) tending to open or close the breaker, and a latch (thermal) to prevent the application of such force, the operation being such that when the latch is released the breaker will snap open under the force.

Similarly, the breaker is provided with a force which tends to close the breaker (the spring), and the application of such force is prevented by a latch (the thermal latch) which operates, when released, to permit the force to snap the contacts together for circuit closing.

It will also be observed that the arm I04 is normally biased on; that the handle positively urges off by a pushing and rocking cam action; that the handle does not push it on but merely releases it so that it will move to on without being urged so to do by the handle; that it automatically moves to ofi when the thermal element warps on overload, without requiring movement of the handle out of "on" position.

It will also be observed that while the means for opening the circuit on overload, namely the means for moving the movable contact I04 from the stationary contact, comprises a magnet IOI, it might well be a spring or the like, operating on the contact I04 when permitted so to do by the movement of the latch I09.

We claim:

1. In a circuit breaker, a stationary contact, a movable contact, spring means normally urging the movable contact towards the stationary contact to maintain the controlled circuit closed, manually operable means arranged to be manipulable to overcome the force of the spring means and thus cause the movable contact to leave the stationary contact or release the movable contact if such contact be away from the stationary contact so that it will be automatically returned to the stationary contact by the spring means without requiring any urging thereon for this purpose by the manually operable means, and circuit current responsive means arranged for normally preventing the movable contact from leaving the stationary contact, except when the latter is caused so to do by the manually operable means, and operable, when energized by a circuit abnormality, for moving and no longer preventing the movable contact from leaving the stationary contact when urged so to do for circuit opening responsive to a circuit abnormality, and means operable without requiring movement of the man ually operable means out of the closed circuit position which it then occupies for causing the movable contact to leave the stationary contact automatically on a circuit abnormality when the movable contact is permitted so to leave by movement of the circuit current responsive means out of its holding or preventing position responsive to a circuit abnormality.

2. In a circuit breaker, a stationary contact, a movable contact, spring means normally urging the movable contact towards the stationary contact to maintain the controlled circuit closed, manually operable means arranged to be manipulable to overcome the force of the spring means and thus cause the movable contact to leave the stationary contact or release the movable contact if such contact be away from the stationary contact so that it will be automatically returned to the stationary contact by the spring means without requiring any urging thereon for this purpose by the manually operable means, and circuit current responsive means arranged for normally preventing the movable contact from leaving the stationary contact, except when the latter is caused so to do by the manually operable means, and operable, when energized by a circuit abnormality, for moving and no longer preventing the movable contact from leaving the stationary contact when urged so to do for circuit opening responslve to a circuit abnormality, and means operable without requiring movement of the manually operable means out of the closed circuit position which it then occupies for causing the movable contact to leave the stationary contact automatically on a circuit abnormality when the movable contact is permitted so to leave by movement of the circuit current responsive means out of its holding or preventing position responsive to a circuit abnormality, the preventing means being so constructed and arranged with respect to the other parts for returning to its normal condition shortly after it has moved out of such normal condition due to a circuit abnormality.

3. A circuit breaker having a movable contact, circuit current responsive means operable on the arising of a circuit abnormality for automatically controlling movement of said contact from closed circuit position and also operable thereafter for automatically controlling return of said contact to closed circuit position, the means including a circuit current controlled part arranged to respond to a circuit abnormality and move out of its normal position and arranged to return spontaneously, but slowly, to its normal position, the breaker having a means for preventing the return of the contact to its closed circuit position until after-the aforesaid part has returned to its normal position.

4. In a circuit breaker, a stationary contact, a movable contact, spring means normally urging the movable contact towards the stationary contact to maintain the controlled circuit closed, manually operable means arranged to be manipulable to overcome the force of the spring means and thus cause the movable contact to leave the stationary contact, and circuit current responsive means arranged for normally preventing the movable contact from leaving the stationary contact, except when the latter is caused so to do by the manually operable means, and operable, when energized by a circuit abnormality, for moving and no longer preventing the movable contact arm from leaving the stationary contact and means operable without requiring movement of the manually operable means out of the closed circuit position which it then occupies for causing the movable contact to leave the stationary contact automatically on a circuit abnormality when the movable contact is permitted so to leave by movement of the circuit current responsive means out of its holding or preventing position responsive to a circuit abnormality.

5. In a circuit breaker, a stationary contact, a movable contact, means for moving the movable contact towards and against the stationary contact, means for moving the movable contact away from the stationary contact on the arising of an overload, an overload controlled holding means for holding the last mentioned means on normal load against causing the movable contact to leave the stationary contact, and releasing the last mentioned means automatically on overload so that it can cause the movable contact to leave the stationary contact, and a handle having a cam connection to the movable contact for manually moving it from the stationary contact against the influence of the first mentioned means with a cam controlled positive and direct bias operation, the handle and the means for causing contact separation automatically on overload being so constructed that such contact 7t separation can take place without requiring movement of the handle out of the closed circuit position which it then occupies.

6. In a circuit breaker, a stationary contact, a movable contact, a spring for moving the movable contact towards and against the stationary contact, means for moving the movable contact away from the stationary contact on the arising of an overload, an overload controlled holding means for holding the means on normal load against causing the movable contact to leave the stationary contact and releasing the means automatically on overload so that it can cause the movable contact to leave the stationary contact, and a handle having a cam connection to the movable contact for manually moving it from the stationary contact against the influence of the spring with a cam controlled positive and direct bias operation, the handle and the means for causing contact separation automatically on overload being so constructed that such contact separation can take place without requiring movement of the handle out of the closed circuit position which it then occupies,

7. In a circuit breaker, a stationary contact, a movable contact, a spring for moving the movable contact towards and against the stationary contact, a magnet arranged to cause the movable contact to move away from the stationary contact on the arising of an overload, an overload controlled holding means for inhibiting such action of the magnet on normal load and causing such action of the magnet automatically on overload, and a handle having a cam connection to the contact for manually moving it from the stationary contact against the influence of the spring with a cam controlled positive and direct bias operation, the handle and the means for causing contact separation automatically on overload being so constructed that such contact separation can take place without requiring movement of the handle out of the closed circuit position which it then occupies.

3. In a circuit breaker, a stationary contact, a movable contact, a spring for moving the movable contact towards, and against the stationary contact, a magnet having an armature for moving the movable contact away from the stationary contact on the arising of an overload, an overload controlled holding means for holding the armature on normal load against causing the movable contact to leave the stationary contact and releasing the armature automatically on overload so that it can cause the movable contact to leave the stationary contact, and a handle having a cam connection to the contact for manually moving it from the stationary con tact against the influence of the spring with a cam controlled positive and direct bias operation, the handle and the means for causing contact separation automatically on overload being so constructed that such contact separation can take place without requiring movement of the handle out of the closed circuit position which it then occupies.

9. In a circuit breaker, a stationary contact, a movable contact, a spring for biasing the movable contact towards and against the stationary contact, a circuit controlled magnet having an armature arranged to operate directly on the movable contact and operating, when the magnet is operatively energized, to move the movable contact away from the stationary contact, unless the armature is held, and an overload release holding means normally holding the armature against moving and causing the movable contact to leave the stationary contact and operating, on overload, to release the armature and permit it to move the movable contact away from the stationary contact.

to. In a circuit breaker, a stationary contact, a movable contact, a spring for biasing the movable contact towards and against the stationary contact, a circuit controlled magnet having an armature arranged to operate directly on the movable contact and operating, when the magnet is operatively energized, to move the movable contact away from the stationary contact, unless the armature is held, and an overload release holding means normally holding the armatime against moving and causing the movable contact to leave the stationary contact and operciting, on overload, to release the armature and permit it to move the contact away from the stationary contact, and a handle for operating directly on the movable contact to bias it away from the stationary contact against the influence oi the spring and to release it so that the spring can bias the movable contact towards and against the stationary contact.

ii. in a circuit breaker, a stationary contact, movable contact, a spring for biasing the movable contact towards and against the stationary contact, a circuit controlled magnet having an armature arranged to operate directly on the movable contact and operating, when the magnet is operatively energized, to move the movable contact away from the stationary contact, unless the armature is held, and an overload release "e against moving and causing the movable contact to leave the stationary contact and operating, on overload, to release the armature and permit it to move the movable contact away from the stationary contact, the holding means thereafter preventing the return of the movable contact to the stationary contact, caused by the spring, except after a time delay required for the holding means to return to its normal condition.

12. In a circuit breaker, a stationary contact, a movable contact, a spring for moving the movable contact towards and against the stationary contact, a magnet arranged to cause the movable contact to move away from the stationary contact on the arising of an overload, an overload controlled holding means for inhibiting such action of the magnet on normal load and to cause such action of the magnet automatically on overload, and a handle having a cam connection to the contact for manually moving it from the stationary contact against the influence of the spring with a cam controlled positive and direct bias operation, and so constructed as not to interfere with the separation of the contacts on overload, the magnet having an armature arranged to move on overload energization of the magnet to a predetermined extent and cause movement of the holding means, if it has not already spontaneously moved, and for no longer inhibiting the circuit opening operation of the magnet.

13. In a circuit breaker, a stationary contact, a movable contact, a spring for moving the movable contact towards and against the stationary contact, a magnet having an armature for moving the movable contact away from the stationary contact on the arising of an overload, an overload controlled holding means for holding the armature on normal load against causing the movable contact to leave the stationary contact and releasing the armature automatically on overload so that it can cause the movable contact to leave the stationary contact, and a handle having a cam connection to the contact for manually moving it from the stationary contact against the influence or the spring with a cam controlled positive and direct bias operation, and so constructed as not to interfere with the separation of the contacts on overload, the magnet having another armature arranged to move on overload energization of the magnet to a predetermined extent and move the holding means, it it has not already spontaneously moved, for releasing the first named armature to move and cause circuit opening.

14. In a circuit breaker, a stationary contact, a movable contact, a spring for biasing the movable contact towards and against the stationary contact, a circuit controlled magnet having an armature arranged to operate directly on the movable contact and operating, when the magnet is energized, to move the movable contact away irom the stationary contact, unless the armature is held, and an overload release holding means normally holding the armature from moving and causing the movable contact to leave the stationary contact and operating, on overload, to release the armature and permit it to move the movable contact away from the stationary contact, the magnet having another armature arranged to move on overload energization oi. the magnet to a. predetermined extent and move the holding means, if it has not already spontaneousiy moved, for releasing the first named armature to move and cause circuit opening,

15. In a circuit breaker, a stationary contact, a movable contact, a spring for biasing the movable contact towards and against the stationary contact, a circuit controlled magnet having an armature arranged to operate directly on the movable contact and operating, when the magnet is energized, to move the movable contact away from the stationary'contact, unless the armature is held, and an overload release holding means normally holding the armature from moving and causing the movable contact to leave the stationary contact and operating, on overload, to release the armature and permit it to move the movable contact away from the stationary contact, the holding means thereafter preventing the return of the movable contact to the stationmy contact, caused by the spring, except after a time delay required for the holding means to return to its normal condition, the magnet having another armature arranged to move on overload energization of the magnet to a predetermined extent and move the holding means, if it has not already spontaneously moved, for releasing the first named armature to move and cause circuit opening.

16. A switch having a stationary contact, a movable contact, a handle arranged for camming the movable contact away from the stationary contact against the influence of a spring which returns the movable contact to the stationary contact when the handle is released to release the movable contact for so returning, a spring for moving the movable contact towards and against the stationary contact, the switch having means operable on overload without requiring movement of the handle out of the closed circuit position which it then occupies for separating the contacts automatically.

17. A switch having a. stationary contact, a movable contact, a handle arranged for camming the movable contact away from the stationary contact against the influence of a spring which returns the movable contact to the stationary contact when the handle is released to release the movable contact for so returning, a spring for moving the movable contact towards and against the stationary contact, the switch having magnetic means operable on overload without requiring movement of the handle out of the closed circuit position which it then occupies for separating the contacts automatically.

WILLIAM H. FRANK. JOSEPH A. MESSING. 

